Intro/Nervous System
In order to understand Parkinson’s and what it does and why certain symptoms occur, you need to understand the nervous system and how it works. The nervous system is the most complicated and fragile of all the body systems. It is the connection between the brain and the body. The nervous system allows us to move on command, to make smooth, precise movements. It is an intricate network of different instruments our body uses in unison to communicate what the mind wants the body to do (http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookNERV.html).
Its starts with the striatum; the central area of the brain. The striatum works with many other parts of the brain one of the more important pieces is the substantia nigra (in this case for balance and coordination). The two work together to send commands that go from the brain to the spinal cord and eventually too its final destination.
The nervous system is a web of nerves 
and the spine is the main highway in which messages are carried through the nerves to other parts of our body branching from the spine. There are many neurotransmitters, which relay the messengers and their messages from nerve cell to nerve cell through out the body. One of the more important transmitters is called dopamine (created in the substantia nigra), which is vital in human movement. Dopamine in balance with another transmitter called acetylcholine which will be reviewed later, makes sure there is no unwanted movement and that the muscle moves smoothly and purposefully.
When a dopamine message is needed, the nerve cell gathers dopamine packets (within itself). The dopamine particles are then discharged from the end of the cell and across the synapse (the space between nerve cells) to another nerve cell. Pockets on the receiving cell collect the dopamine. A chemical called MAO-B, which hangs out around the synapse, breaks down any extra dopamine that did not originally fit the pockets. This is a crucial step in the wanted control of the muscle. Too much or too little dopamine creates problems and may create “unsmooth” muscle movement, like stuttering. The dopamine will eventually reach its destination and will then send the message of what the brain wants the body to do, thus creating thought into motion.
There is one other neurotransmitter mentioned earlier, which works in unison with dopamine, it is called acetylcholine. Depending on what your brain wants to do, it sends a specific balance of acetylcholine and dopamine. It is especially important in the smooth movement of our body. This is where a major problem of Parkinson’s occurs along with process’ earlier in the operation of movement com(http://www.parkinsonsinfo.com/about_parkinsons).
What is Parkinson’s
In Parkinson’s, for reasons that have not been pinpointed, 
nerve cells in the substantia nigra begin to produce less and less dopamine. This causes a dramatic drop in the amount of dopamine manufactured. In addition the MAO-B continues to break down the dopamine when it cross’ the synapse to the other nerve cell as if there was the normal amount of dopamine being produced, this only gets worse with the more synapses the dopamine has to cross, and there are millions of nerves in the body. As result in the end there is a very small sum of dopamine left in the brain that can be used. This throws off the normal balance between dopamine and acetylcholine (Parkinson’s: Inside the Nervous System by Dr. Longstreath).
Symptoms
As a consequence of the disproportion of dopamine and acetylcholine, there is a clear lack of coordination in a persons movements. This usually first appears as a tremor in the hand or shaking. Many times the shudders begin on one side of the body and from there it only spreads. Other common results of Parkinson’s consist of slowed down movement, stiff limbs, a sort of shuffling “unenergetic” walk, hunched posture, and in extreme cases the inability to move at all. Parkinson’s patients furthermore often show dubbed down facial expressions (and in movement in general), slow quite speech, or speech impairments, disturbed sleep, even personality changes and depression. The symptoms are the only way a doctor can verify whether the disorder is Parkinson’s or not, there are no tests that can give the doctor a definite answer. The severity of the symptoms normally gets worse over time although the progression of illness varies from three to thirty years.
How Do People Get Parkinsons?
So how does such a common disease infect a person? The answer unfortunately is that no one knows why people get the disorder, there are no links to cases of Parkinson’s other than the age. Its still quite a mystery. Only recently have scientists discovered that Parkinson’s is inheritable, and thus they still haven’t figured out what gene it is inherited on. Also just recently (stated before) they have figured out that there are basically two types of the disease.
Types of Parknson’s
It has been widely agreed upon that there are two sub types of Parkinson’s. The sub groups are identified by the age in which diagnosed and the rate of progression of the illness. The “classical” Parkinson’s by and large appears before the age of sixty and progress’ very slowly, while the “abnormal” Parkinson’s tends to develop after the age of seventy and progress’ very quickly. Generally speaking the symptoms of both are very similar.
There are also several disorders or deficiencies that have been labeled as “Parkinsonisms”. People get “Parkinsonisms” and Parkinson’s mixed up all the time, but they are very different. Parkinson’s is a way of describing disorders that are similar to Parkinson’s, as in there are similar symptoms but they are not Parkinson’s disease. These conditions can arise from specific brain infections or insufficiencies, effects from strokes, as a result or as symptoms of others diseases, and even as side affects of some medicines. Obviously medicines today aren’t flawless, this also goes for the drugs developed for Parkinson’s, but medication is what has made Parkinson’s today so flexible and so much more easy to live with.
Treatments
There are many treatments, or medicines that are out there; some more popular than others. 
They all work in different ways to slow down the destruction of the dopamine or to substitute it with something else. Sinemet one of the most effective of the medicines, is a drug that replaces dopamine. Sinemet, once in the brain is converted into dopamine for the nerve cells to use as neurotransmitters (http://www.parkinsonsinfo.com/about_parkinsons).
Symmetrel makes it easier for the nerve cells producing dopamine to release it. This medication is better for the milder cases of Parkinson’s because there is no artificial dopamine or substitutes which can cause serious side effects (http://www.parkinsonsinfo.com/about_parkinsons).
Artane and Cogentin take a different approach to watering down the symptoms of Parkinson’s. What these two drugs do is manipulate the balance of dopamine and acetylcholine. They do this by limiting the activity of acetylcholine. This significantly helps reduce the tremors and inaccuracies of body motion. Once again this really can only be used in the early stages of Parkinson’s or a mild case of it (http://www.parkinsonsinfo.com/about_parkinsons).
The most unique of all the medications is Eldepryl, it works differently than all the other agents. Eldepryl blocks the chemical MAO-B (the one that eats up lingering dopamine) from breaking up the dopamine while crossing the synapse. This keeps dopamine working at a hundred percent efficiency, and makes the most of all the dopamine that’s left (http://www.parkinsonsinfo.com/about_parkinsons).
There are other "treatments", which can help with Parkinson's such as excercise, therapy, nutrition, etc..., which are regarded in the Daily Living portion of this web page
Developing Cures
In late of 2001, scientists came upon a probable cure for Parkinson’s. 
When testing with animals, mice with Parkinson’s to be specific, scientists found that after surgically implanting dopamine producing cells from an stem cell into the mouse’s head, they join up with the rest of the mouse’s brain cells. The embryo brain cells develop properly and thus produce dopamine and secrete dopamine when needed and commanded by the brain. Thus the symptoms of Parkinson’s in the mouse were cured. The mouse no longer had trouble moving or problems with tremors and such (http://www.webmd.com/content/article/24/1833_50420).
The big problem that scientists face with stem cells now is that the brain cells aren’t always developed from a stem cell. The scientists want the cells to embody dopamine and produce it, but this doesn’t always happen, there are many kinds of brain cells in the brain, and at this point it is random, in which what the stem cell will produce. The goal is to get the right stem cells to manufacture particular types of brain cells, and of course in this case, cells that produce dopamine for the brain are the target cells (http://www.webmd.com/content/article/24/1833_50420).
There have been other attempts to cure Parkinson’s, one notable method is with another type of surgery. Scientist or Doctors have tried to implant brain tissue into the heads of Parkinson’s patients, but rarely has that been met with any success. In some rare cases patients have suffered fatal affects from this operation.
Cures have been estimated to be five to ten years in the future, not so long from now. Parkinson’s a “disease of the past” is a viable goal, thanks to the discovery and research of stem cells. The stem cell concept is the big step for mankind to overcome, intertwined with moral issues and high risks, it’s a step that is needed to be taken together as a nation or ideally as a world.